Line Current Offset calibration

[bilalfarooq002]

Hi, i am trying to calibrate the ATM90E26 metering IC using this library and i have also created some custom functions to calibrate voltage gain, current gain etc, but when i try to calibrate Line Current offset by writing offset value to IoffsetL (register 35H) there is very small change in the Line Current rms. But whatever value i put in the offset register i am not able to make it zero.

here are voltage and current gains ugain = 0x67A3 igain = 0x1AC6

i have tested the voltage and current gain values and i am getting accurate values with less than 1% error.

here is the code where i am calculating the current offset:

this is the same formula as described in the application note, furthermore i have also tested by putting in value from 0 to 50000 in 16 bit IoffsetL register just to see if maybe i was putting wrong value of current offset and also to see the behavior of current offset. I noticed the no matter what value i put in the current offset it never makes the Irms current value zero.

Here is the place where i am setting the current offset and current, voltage gain:

here is the place where i am apply the calibration in the code, this is in the prebuilt CalibrateEnergyIC() function:

If anyone has done current offset calibration, please share your experience, thanks

[ripper121]

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